to start plain old X. If the mouse moves, super. If it doesnt, upon killing X (either via CTRL+ALT+BACKSPACE or Alt+SysRq+K) it should tell you where it logged its output I believe (and a bit up on the terminal it should show any errors encountered - some innocuous, some not so much)

Yes I am running gentoo in a vm, to test it out.
I didn't want to wipe everything, then unsuccessfully install gentoo.
Output: http://bpaste.net/show/56144
weird. Xorg.log.0.old isn't jumbled, but the normal one is